Continuous flow centrifuge apparatus



March 31, 1964 D. F. MITCHELL CONTINUOUS FLOW CENTRIFUGE APPARATUS 4 Sheets-Sheet 1 Filed Jan. 15, 1962 lzveazov: David FMW ffowzqy March 31, 1964 D. F. MITCHELL CONTINUOUS FLOW CENTRIFUGE APPARATUS 4 Sheets-Sheet 2 Filed Jan. 15, 1962 March 31, 1964 D. F. MITCHELL 3,127,342

CONTINUOUS FLOW CENTRIFUGE APPARATUS Filed Jan. 15, 1962 4 Sheets-Sheet 3 March 31, 1964 D. F. MITCHELL 3,127,342

CONTINUOUS FLOW CENTRIFUGE APPARATUS Filed Jan. 15, 1962 4 Sheets-Sheet 4 United States Patent 3,127,342 CON'I'INUUUS FLOW CENTRIFUGE APPARATUS David F. Mitchell, Tewksbury, Mass, assignor to International Equipment Company, Boston, Mass, a corporation of Massachusetts Filed Jan. 15, 1962, Ser. No. 166,038 6 Claims. (Cl. 23321) This invention relates to continuous flow centrifuges and to devices for use in such apparatus including rotor and stator sections providing concentric delivery and return passageways.

In a continuous flow centrifuge, it is necessary to provide for the delivery of a liquid into the centrifuge basket from an externally located delivery conduit and for the return of liquid therefrom to a return conduit which 18 also located outside the basket. Usually, but not necessarily, the basket is provided with a coil whose inlet is connected to the delivery conduit and whose outlet is connected to the return conduit. Continuous flow centrifugation presents a wide range of problems such as the prevention of an aerosol eflect, the necessity of structures that facilitate cleaning, sterilizing, and servicing operations, and the control of the flow to prevent pressure build-ups that might cause tubing ruptures or interfere with desired centrifugal effects due to excessive heads on the coil contents.

The general objective of the present invention is to overcome these difficulties and, in accordance with it, that objective is attained by providing, in apparatus of the above summarized type, a device comprising co-axial rotor and stator sections, the rotor section, in use, extending axially into and being rotatable with the centrifuge basket. The rotor section has, in its lower end, spaced delivery and return ports. The lower rotor section end aiso has a chamber provided with an annular shoulder located above its bottom with the delivery port opening into the chamber below the shoulder and with the return port opening therein above that shoulder.

The stator section has a circular flange pendant above the chamber shoulder and includes a pair of concentric, axial conduits whose upper ends extend above the rotor section. One conduit opens into the chamber below the shoulder thereof and has, adjacent its upper end, a delivery port for connection with the delivery conduit and is a delivery passageway. The other conduit has return ports, one above the rotor section for connection with the return conduit and one opening through the flange and is a return passageway.

A particular object of the invention is to provide the flange of the stator section with one and preferably a series of surfaces, disposed to intercept fluid in the chamber above the shoulder, which fluid is under the influence of centrifugal force when the centrifuge is in service. These intercepting surfaces divert the fluid into the return passageway, utilizing the kinetic energy of the liquid in effecting its positive upward flow.

Another particular objective of the invention is to provide a rotor section which includes upper and lower members and a stator section which also includes upper and lower members having alined axial bores in which there is a tubular member whose bore defines the delivery passage and whose outside diameter is so related to the inside diameter of the alined bores, in a zone inclusive of the return ports, as to establish a clearance adequate for the return passageway.

It is preferred that, whether or not positive circulation is provided, there be an unsealed clearance between the chamber above the flange and the chamber below the flange although the delivery and return passageways may be positively isolated from each other. With such an unsealed clearance, any flow between the chambers is inconsequential when the delivered volume is not beyond the capacity of the coil. At the same time, excess liquid, as for example if the coil becomes clogged, bypasses the coil.

Another objective of the invention is to provide rotor and stator sections that are so sealed as to avoid any aerosol effect.

Yet another object of the invention is to provide that the devices can be readily assembled and disassembled to ensure ease and convenience in cleansing the parts or making seal replacements, for example.

In the accompanying drawings, there is shown an illustrative embodiment of a centrifuge in accordance with the invention from which these and other of its objectives, novel features, and advantages will be readily apparent.

In the drawings:

FIGURE 1 is a top plan view of a centrifuge basket in accordance with the invention,

FIGURE 2 is a vertical section through the centrifuge basket on a slightly increased scale,

FIGURE 3 is a vertical section through the contra-flow device on a substantially increased scale,

FiGURE 4 is a section taken approximately along the indicated lines 4-4 of FIGURE 2, and

FIGURE 5 is an exploded view showing in perspective the seal between the rotor and stator sections of the device.

As indicative of a centrifuge drive, there is shown a hub 16 in which the driving member 11 is journalled. The driving member is shown as having an upwardly and inwardly tapering portion 12 receiving the correspondingly tapered seat 13 in the axial, upwardly disposed hub 14 of the basket 15. The upper end of the spindle is threaded to receive the threaded socket 16 at the bottom of the lower housing member 17 of the generally indicated contra-flow device 18. The bottom end of the housing member 17 has a flange 19 for clamping engagement with the upper end of the hub 14 when the member 1'7 is threaded onto the spindle iii.

A cover 29 is attached to the periphery of the basket 15 as by screws 21 and has a depending flange 22 entrant of the mouth of the basket 15 and provided with a basket engaging annular seal 23. The cover 29 has an axial port defined by a depending, annular flange 24 provided with an annular seal 25 engaging the housing member 17 below its exteriorly threaded mouth 26.

The housing member 17 has spaced ports 27 and 28 and, the invention is illustrated with a coil 2? within the basket 15 having its inlet connected to the port 27, via a conduit 36, by means of fittings 30A and 39B and its outlet connected to the port 28, via a conduit 31, by means of fittings 31A and 31B. As coils may be used that vary in size and in the size of the tubing as well as in the material from which the tubing is formed, the fittings may be varied as a means of supplying balancing weight to the basket when readied for service.

The housing member 17 has a chamber 32 having an intermediate, annular shoulder 33 dividing the chamber into upper and lower portions. Adjacent but below the exten'orly threaded mouth 26 of the housing member 17, the chamber 32 has a shoulder 34 supporting a sleeve 35 and, above the shoulder 34, the chamber 32 is dimensioned to closely confine the sleeve 35 and preferably the sleeve 35 is provided with a seal 36 engaging that portion of the chamber 32. The inlet port 27 opens into the lower portion of the chamber 32 while the return port 28 opens through the upper face of the shoulder 33 into its upper portion.

A cover 37 has an interiorly threaded mouth 38 enabling it and the housing member 17 to be interconnected and when thus connected, they establish the rotor section of the device 18. The upper end of the interior of the cover 37 is dimensioned as at 39 to closely confine the sleeve 35 which is shown as having a cover-engaging seal 40. The cover 37 also has a central port 41 upwardly through which the upper end of the generally indicated stator section 42 protrudes.

The stator section 42 comprises a lower conduit member 43 having its upper end 44 of reduced diameter and threaded as at 45. An upper conduit member 46 has a downwardly opening mouth 47 which is threaded to enable it to be connected to the lower conduit member 43. The conduit members 43 and 46 have axial bores 48 and 49, respectively, the axial bore 48 extending from end-toend of the member 43 and being in alinement with the bore 49 when the conduit members 43 and 46 are threaded together. Seated on the conduit member 46 is a separate cap portion 46A which has a port 50 adapted to have the delivery conduit 51 attached thereto and counterbored as at 52 when it opens into the axial bore 49. A seal 53 is provided between the upper end 44 of the conduit member 43 and the mouth of the upper conduit member 46 above its threads and the upper conduit member 46 has a seal 54 which engages the upper part of a tubular member 55 which has its upper extremity 56 dimensioned for entry into the counterbore 52. Apart from production costs, the cap portion 46A and the tubular member 55 are to be regarded as integral. The lower end of the tubular member 55 extends beyond the lower end of the lower housing member 17 and into the lower portion of the chamber 32. The conduit member 43 has, adjacent the lower end of its bore 48, a seal 57 engaging the tubular member 55 which is the delivery passageway.

Below the seal 54, the upper conduit member 46 has a laterally disposed return port 58 adapted to have the return conduit 59 attached thereto. The conduit member 43 has a circular flange 60 adjacent its lower extremity and a laterally disposed return port 61 opens therethrough and is shown as including a plurality of scoop-like surfaces 62, see FIGURE 4, disposed to intercept fluid in the chamber 32 above its shoulder 33. The tubular member 55 is of reduced diameter in a zone 63 inclusive of the return ports 58 and 61, thus to define therewith a return passageway.

It will be noted from FIGURE 3 that the sleeve 35 is provided with a retaining ring 64 between which and the upper end of the cover 37 there is clamped the outer race 65 of a generally indicated ball bearing unit 66. The inner race 67 of that unit is clamped between the mouth of the upper conduit member 46 and a shoulder 68 with which the lower conduit member 43 is provided. By these or equivalent means, the stator section 42 is sup ported with the flange 60 pendant above the shoulder 33. In this connection, it will be noted that the cap portion 46A is provided with flattened faces 69, see FIGURE 1, engaged by the side portions of a loop 70 at the end of an arm 71 supported by an upright 72 at one side of the basket 15 by a bracket 73 clamped to the hub 10. By these or other means the stator section 42 of the device is held against rotation.

A seal of the shaft seal type between the rotor and stator sections is generally indicated at 74. A satisfactory type of such a seal comprises a ring 75 seated against the retaining ring 64 and having an annular seal 76 in engagement with the sleeve 35. The ring 75 is provided with spaced depending lips 77 for entry between the ends of annular rib sections 78 of the holder 79 with which rib sections the lips 77 then engage on partial rotation thus to interconnect the ring 75 and the holder 76 with a spring element 80 between them. Preferably the holder 79 has a sleeve portion 79A fitting within the ring 75 and provided with a seal 81 for sealing engagement therewith. The holder 75 is provided with a ring 82, typically a carbon ring, for engagement with the upper face of the 4 flange 60 with their mutually engaged surfaces lapped to an extent ensuring the effectiveness of the seal.

From the foregoing, it will be apparent that both the rotor and stator sections are sealed against leakage while leakage between them is effectively prevented by the seal 74. At the same time, the sections are adapted to be readily disassembled and serviced as required and as readily re-assembled.

In operation, the effective sealing of the several parts of each section and the seal between the sections ensures against an aerosol effect while the use of the intercepting surfaces 62 ensures a positive return flow of the liquid. With or without the surfaces 62 and their flow assisting function, the fact that the space between the upper and lower portions of the chamber 32 is unsealed has the substantial advantage that, so long as the flow through the delivery system is within reasonable limits, inter-passageway flow is either non-existent or inconsequential but should the flow to the coil exceed those limits, then the excess is by-passed to avoid tube ruptures, excessive heads on the tube contents, or like objectionable consequences.

I claim:

1. In a continuous flow centrifuge of the type having a basket into which and from which liquid is to be circulated via concentric passageways axially of the basket when connected to exterior delivery and return conduits, respectively, a device axially of said basket and comprising rotor and stator sections, said rotor section being connected to said basket to rotate therewith and having a chamber and including a lower housing member and a cover threaded thereon, the lower end of said member being within said basket when the rotor section is connected thereto, said chamber having an annular shoulder above its bottom, a delivery port opening into the chamber below said shoulder, and a return port opening into said chamber above said shoulder, and a ball bearing unit within the chamber but above said shoulder rotatably connecting said sections, the outer race of said unit being clamped between said housing member and said cover, and said stator section including a conduit member having an axial bore opening through its lower end and provided with a circular flange between said shoulder and said unit, the upper end of said conduit member being above said rotor section, and a tubular member in said axial bore opening into said chamber below said shoulder, the upper end of said conduit member having a delivery port opening into said tubular member for connection to said delivery conduit, said tubular member and said chamber below said shoulder being the fluid delivery passageway, said conduit member having return ports in communication with said axial bore, one opening into said chamber above said shoulder and the other being above said rotor section for connection to said return conduit, said axial bore and said tubular member being dimensioned, in a zone inclusive of said return ports, to provide a conduit defining clearance, said Zone and said chamber above the shoulder being the fluid return passageway.

2. In a continuous flow centrifuge of the type having a basket into which and from which liquid is to be circulated lvia concentric passageways axially of the basket when connected to exterior delivery and return conduits, respectively, a device axially of said basket and comprising rotor and stator sections, said rotor section being connected to said basket to rotate therewith and having a chamber and including a lower housing member and a cover threaded thereon, the lower end of said member being within said basket when the rotor section is connected thereto, said chamber having an annular shoulder above its bottom, a delivery port opening into the chamber below said shoulder, and a return port opening into said chamber above said shoulder, and a ball bearing unit within the chamber but above said shoulder rotatably connecting said sections, the outer race of said unit being clamped between said housing member and said cover, and said stator section including a conduit member having an axial bore opening through its lower end and provided with a circular flange between said shoulder and said unit and a sealing unit below said bearing unit and including an annular member in siding engagement with the upper surface of said flange, the upper end of said conduit member being above said rotor section, and a tubular member in said axial bore opening into said chamber below said shoulder, the upper end of said conduit member having a delivery port opening into said tubular member for connect-ion to said delivery conduit, said tubular member and said chamber below said shoulder being the fluid delivery passageway, said conduit member having return ports in communication with said axial bore, one opening into said chamber above said shoulder and the other being above said rotor section for connection to said return conduit, said axial bore and said tubular member being dimensioned, in a zone inclusive of said return ports, to provide a conduit defining clearance, said zone and said chamber above the shoulder being the fluid return passageway.

3. In a continuous flow centrifuge of the type having a basket into which and from which liquid is to be circulated via concentric passageways axially of the basket when connected to exterior delivery and return conduits, respectively, a device axially of said basket and comprising rotor and stator sections, said rotor section being connected to said basket to rotate therewith and having a chamber and including a lower housing member and a cover threaded thereon, the lower end of said member being within said basket when the rotor section is connected thereto, said chamber having an annular shoulder above its bot-tom, a delivery port opening into the chamber below said shoulder, and a return port opening into said chamber above said shoulder, and a ball bearing unit within the chamber but above said shoulder rotatably connecting said sections, the outer race of said unit being clamped between said housing member and said cover, and said stator section including a conduit member having an axial bore opening through its lower end and provided with a circular flange between said shoulder and said unit, the upper end of said conduit member being above said rotor section, and a tubular member in said axial bore opening into said chamber below said shoulder, the upper end of said conduit member having a delivery port opening into said tubular member for connection to said delivery conduit, said tubular member and said chamber below said shoulder being the fluid delivery passageway, said conduit member having return ports in communication with said axial bore, one opening downwardly througth said flange and including a series of circumferentially spaced surfaces in the lower face thereof, each in the form of a pump scoop, and the other being above said rotor section for connection to said return conduit, said axial bore and said tubular member being dimensioned, in a zone inclusive of said return ports, to provide a conduit defining clearance, said zone and said chamber above the shoulder being the fluid return passageway.

4. In a continuous flow centrifuge of the type having a basket into which and from which liquid is to be circulated via concentric passageways axially of the basket when connected to exterior delivery and return conduits, respectively, a device axially of said basket and comprising rotor and stator sections, said rotor section being connected to said basket to rotate therewith and having a chamber and including a lower housing member and a cover threaded thereon, the lower end of said member being within said basket when the rotor section is connected thereto, said chamber having an annular shoulder above its bottom, a delivery port opening into the chamber below said shoulder, and a return port opening into said chamber above said shoulder, and a ball bearing unit within the chamber but above said shoulder rotatably connecting said sections, the outer race of said unit being clamped between said housing member and said cover, and said stator section including a conduit member having an axial bore opening through its lower end and provided with a circular flange between said shoulder and said unit, the upper end of said conduit member being above said rotor section, and a tubular member in said axial bore opening into said chamber below said shoulder, said conduit member including upper and lower sections threaded together, each conduit section including a shoulder, the inner race of said bearing unit being clamped between said shoulders, the upper end of said conduit member having a delivery port opening into said tubular member for connection to said delivery conduit, said tubular member and said chamber below said shoulder being the fluid delivery passageway, said conduit member having return ports in communication with said axial bore, one opening into said chamber above said shoulder and the other being above said rotor section for connection to said return conduit, said axial bore and said tubular member being dimensioned, in a Zone inclusive of said return ports, to provide a conduit defining clearance, said zone and said chamber above the shoulder being the fluid return passageway.

5. In a continuous flow centrifuge of the type having basket into which and from which liquid is to be circulated via concentric passageways axially of the basket when connected to exterior delivery and return conduits, respectively, a device axially of said basket and comprising rotor and stator sections, said rotor section being connected to said basket to rotate therewith and having a chamber and including a lower housing member and a cover threaded thereon, the lower end of said member being within said basket when the rotor section is connected thereto, said housing member having an annular shoulder above its bottom and a second annular shoulder between the first named shoulder and its cover receiving end, a sleeve on said second shoulder and extending upwardly over the joint defined by the ends of the housing member and cover, and including an inwardly disposed retaining ring between its ends, said housing member also having a delivery port opening into the chamber below the first named shoulder and a return port opening into said chamber above said first named shoulder, and a ball bearing unit within the chamber rotatably connecting said sections, the outer race of said unit being clamped between said cover and said retaining ring, and said stator section including a conduit member having an axial bore opening through its lower end and provided with a circular flange between said shoulder and said unit, the upper end of said conduit member being above said rotor section, and a tubular member in said axial bore opening into said chamber below said shoulder, the upper end of said conduit member having a delivery port opening into said tubular member for connection to said delivery conduit, said tubular member and said chamber below said shoulder being the fluid delivery passageway, said conduit member having return ports in communication with said axial bore, one opening into said chamber above said shoulder, and the other being above said rotor section for connection to said return conduit, said axial bore and said tubular member being dimensioned, in a zone inclusive of said return ports, to provide a conduit defining clearance, said zone and said chamber above the shoulder being the fluid return passageway.

6. In a continuous flow centrifuge of the type having a basket into which and from which liquid is to be circulated via concentric passageways axially of the basket when connected to exterior delivery and return conduits, respectively, a device axially of said basket and comprising rotor and stator sections, said rotor section being connected to said basket to rotate therewith and having a chamber and including a lower housing member and a cover, said cover and housing member including overlapping cylindrical ends threaded together, the lower end of said member being within said basket when the rotor section is connected thereto, said housing member having an annular shoulderabove its bottom and a second annular shoulder between the first named shoulder and its cover receiving end, a sleeve on said second shoulder and extending upwardly over the joint defined by the ends of the housing member and cover, and including an inwardly disposed retaining ring between its ends, said housing member also having a delivery port opening into the chamber below the first named shoulder and a return port opening into said chamber above said first named shoulder, and a ball bearing unit within the chamber rotatably connecting said sections, the outer race of said unit being clamped between said cover and said retaining ring, and said stator section including a conduit member having an axial bore opening through its lower end and provided with a circular fiange between said shoulder and said unit, and a sealing unit below said bearing unit and including an annular member in sealing engagement with the upper surface of said flange, the upper end of said conduit member being above said rotor section, and a tubular member in said axial bore opening into said chamber below said shoulder, the upper end of said conduit member having a delivery port opening into said tubular member for connection to said delivery conduit, said tubular member and said chamber below said shoulder being the fluid deliverypassageway,'said conduit member having return ports in communication with said axial bore, one opening into said chamber above said shoulder and the other being above said rotor section for connection to said: return conduit, said, axial bore and said tubular member being dimensioned, in a zone inclusive of said return ports, to provide a conduit defining clearance, said zone and said chamber above the shoulder being the fluid return passageway.

References Cited in the file of this patent UNITED STATES PATENTS 

1. IN A CONTINUOUS FLOW CENTRIFUGE OF THE TYPE HAVING A BASKET INTO WHICH AND FROM WHICH LIQUID IS TO BE CIRCULATED VIA CONCENTRIC PASSAGEWAYS AXIALLY OF THE BASKET WHEN CONNECTED TO EXTERIOR DELIVERY AND RETURN CONDUITS, RESPECTIVELY, A DEVICE AXIALLY OF SAID BASKET AND COMPRISING ROTOR AND STATOR SECTIONS, SAID ROTOR SECTION BEING CONNECTED TO SAID BASKET TO ROTATE THEREWITH AND HAVING A CHAMBER AND INCLUDING A LOWER HOUSING MEMBER AND A COVER THREADED THEREON, THE LOWER END OF SAID MEMBER BEING WITHIN SAID BASKET WHEN THE ROTOR SECTION IS CONNECTED THERETO, SAID CHAMBER HAVING AN ANNULAR SHOULDER ABOVE ITS BOTTOM, A DELIVERY PORT OPENING INTO THE CHAMBER BELOW SAID SHOULDER, AND A RETURN PORT OPENING INTO SAID CHAMBER ABOVE SAID SHOULDER, AND A BALL BEARING UNIT WITHIN THE CHAMBER BUT ABOVE SAID SHOULDER ROTATABLY CONNECTING SAID SECTIONS, THE OUTER RACE OF SAID UNIT BEING CLAMPED BETWEEN SAID HOUSING MEMBER AND SAID COVER, AND SAID STATOR SECTION INCLUDING A CONDUIT MEMBER HAVING AN AXIAL BORE OPENING THROUGH ITS LOWER END AND PROVIDED WITH A CIRCULAR FLANGE BETWEEN SAID SHOULDER AND SAID UNIT, THE UPPER END OF SAID CONDUIT MEMBER BEING ABOVE SAID ROTOR SECTION, AND A TUBULAR MEMBER IN SAID AXIAL BORE OPENING INTO SAID CHAMBER BELOW SAID SHOULDER, THE UPPER END OF SAID CONDUIT MEMBER HAVING A DELIVERY PORT OPENING INTO SAID TUBULAR MEMBER FOR CONNECTION TO SAID DELIVERY CONDUIT, SAID TUBULAR MEMBER AND SAID CHAMBER BELOW SAID SHOULDER BEING THE FLUID DELIVERY PASSAGEWAY, SAID CONDUIT MEMBER HAVING RETURN PORTS IN COMMUNICATION WITH SAID AXIAL BORE, ONE OPENING INTO SAID CHAMBER ABOVE SAID SHOULDER AND THE OTHER BEING ABOVE SAID ROTOR SECTION FOR CONNECTION TO SAID RETURN CONDUIT, SAID AXIAL BORE AND SAID TUBULAR MEMBER BEING DIMENSIONED, IN A ZONE INCLUSIVE OF SAID RETURN PORTS, TO PROVIDE A CONDUIT DEFINING CLEARANCE, SAID ZONE AND SAID CHAMBER ABOVE THE SHOULDER BEING THE FLUID RETURN PASSAGEWAY. 